Foods with textural contrast, such as crispy baked snacks with a creamy filling, can be appealing to a broad spectrum of consumers. These dual texture foods may include a lower water activity (Aw) crispy component, such as a cracker, and a filling component, such as a creamy, shelf-stable filling. The filling component, which may be lipid-based, typically exhibits the desired creamy texture from relatively small particles dispersed in a lipid continuous phase. However, such lipid-based filling components tend to have the shortcoming that the dispersion structure can be thermally destabilized in some instances leading to oiling-out and loss of creaminess upon heating. It is believed that such thermal destabilization may be the result of aggregation of the small particles leading to lipid separation from other filling ingredients. Thus, such shortcoming renders manufacture of the dual texture snack challenging.
In general, two approaches are commonly used to manufacture such dual texture snacks. By one approach, the crispy or cracker component, which is usually obtained from a dough, can be baked prior to applying the filling. In this case, the filling is not exposed to baking temperatures, and the shortcoming discussed above can be minimized or avoided. However, this approach can have limitations in terms of processing and limit product configurations, for example, to sandwich-type products. Another approach is to prepare a filled dough with the filling component injected therein and then baking the dough and the filling together. This approach is limited by the thermal instability of the filling component at baking temperatures, such as temperatures of about 110° C. or higher, commonly used for crackers, biscuits, baked chips, or other extruded/baked snacks. When the prior filling compositions are exposed to such baking temperatures, it can suffer from product defects such as boiling-out, oiling-out, loss of smoothness, and discoloration.
To address the stability problems of the filling component under commercial baking conditions, prior creamy filling compositions were generally formulated as water-based systems containing a hydrophilic liquid or aqueous continuous phase and dispersed oil droplets as an oil-in-water emulsion. The emulsion was then combined with relatively high amounts of water activity (Aw) lowering humectants (such as polyhydric alcohols like polyols, glycerol, sorbitol or other carbohydrate-based humectants such as polydextrose and the like), thickeners, and/or gelling agents (such as hydrocolloids, proteins, starches, and the like) to improve emulsion stability at commercial baking temperatures. See, for example, U.S. Pat. Nos. 4,752,494; 5,529,801; 6,863,911; 6,905,719; and 6,905,720. These prior fillings, however, are generally unacceptable from an organoleptic standpoint because they tend to be syrupy or gummy in texture and undesired as a creamy, savory filling (such as a cheese-flavored filling) due to unwanted sweetness and unpleasant aftertaste from the humectants (such as bitter aftertaste from glycerol). To achieve bake stability, such prior compositions tended to compromise desired organoleptic qualities due to these additional ingredients that tended to alter the desired taste, texture, and/or overall flavor of the filling and/or otherwise tended to lessen the eating experience expected by the consumer.
One example of a prior cheese-flavored filling is a low Aw, oil-in-water emulsion composition. In this prior filling, the water or hydrophilic phase is mainly made of glycerol (or other polyhydric alcohols), polydextrose syrup, corn syrup, and mixtures thereof. Such construction of these emulsion fillers may be generally stable at low temperatures, but under baking conditions the fillers are typically prone to boil-out or bleed-oil as the lipid phase can potentially undergo coalescence resulting in phase separation or inversion. In addition, the water in the hydrophilic continuous phase may also escape from the filling at baking temperatures resulting in blow-out of the dough or unwanted large voids in the dough envelope. These prior liquid-liquid emulsions also tend to be interfacially dynamic and their stability can be highly sensitive to shear, processing (e.g., extrusion, etc.), handling, and storage conditions.